1. Field of the Invention
The present invention relates to a device for producing an on-line image of a body part into which a contrasting agent has been introduced, and more particularly, to an ultrasound device which detects the contrasting agent in the body part and produces an on-line display of the results for analysis of fluid flow into the body part.
2. Description of the Related Art
With regard to the basic concept of ultrasound, an ultrasound device makes a frame out of a plurality of lines and ultrasound waves are transmitted in different directions. Typically, this is done at a rate of 30 to 60 frames per second. Specifically in relation to the heart, a doctor or technician looks at how the heart beats in real time by making a real time picture of the heart where one can see it contracting. What ultrasound has tried to do in the past is to try to see functionally whether the walls of the heart are moving and determine from that whether there is blood getting to the heart tissue. On the ultrasound image, blood is dark as it is made out of red blood cells and the heart tissue is very bright. The heart tissue scatters back the ultrasound with a significant amount of energy, whereas the blood does not really scatter the ultrasound much. Upon viewing an ultrasound image of the heart, the heart tissue would appear somewhat speckly and bright and the blood would appear fairly dark. Techniques have been known that look at the blood and how it moves, for example using color flow in Doppler. But a two-dimensional image typically looks very bright for the heart tissue and one would not see anything in the chambers of the heart.
Further, the doctor or technician may be concerned about a stenosis or blockage in the heart and want to determine blood flow in the heart. The above techniques result in indirect measures of blood flow in the heart tissue, e.g., the myocardium. However, more direct techniques of determined blood flow are desired.
Another technique, which is more direct, involves injecting a contrasting agent, which has little microbubbles, into the vein of a subject. The microbubbles are small enough to make it through the capillaries of the subject. The microbubbles are basically some type of shell, like albumen, plastic or sugar, and contain a gas like air or nitrogen or perfluorocarbon. All these microbubbles scatter back the ultrasound by making the blood more echogenic. With these microbubbles, the doctor or technician wants to watch where the blood travels in the tissue.
Since this is a more direct way of looking at whether there is a blood flow problem, such a technique is more sensitive and a better test than looking at the motion of the heart. The main concept behind using contrast agents with ultrasound is to enable a doctor or technician to see blood flow in the heart.
If there is a blockage in the heart, there is going to be less of these microbubbles flowing into various portions of the heart, such as the myocardium. Different parts of the heart that are fed by different coronary arteries would be affected by the blockage. If one part of the ultrasound image is dark and another part is bright, the doctor or technician would know that there probably is a problem with the coronary artery that feeds the dark part of the heart.
Upon studying the use of contrasting agents with ultrasound, it was discovered that the ultrasound destroyed the microbubbles. By destroying the microbubbles and watching how fast they come back, the doctor or technician could determine not only how many microbubbles are in any part of the heart, she could determine how fast they were moving, which is the blood flow. By destroying the microbubbles and then timing how fast they come back, it is possible to determine which areas of the heart have slow flow and which areas have rapid flow, through a determination of how quickly the number of microbubbles change in the various parts of the heart.
A high powered frame of an ultrasound is emitted from the ultrasound device to destroy the microbubbles and lower powered frames of the ultrasound are emitted to watch the microbubbles come back. Different timing arrangements may be usable to determine the blood flow using a contrasting agent having the microbubbles.
The blood flow can be modeled as an exponential where blood flow equals A(1xe2x88x92ebt). It is well known to discuss perfusion after the microbubbles have been destroyed based on the value A.
FIG. 1 is a diagram showing a conventional system which uses a contrasting agent to analyze blood flow in different parts of the body, particularly the heart. A contrasting agent is injected into a vein of a patient so as to flow in the blood stream. An ultrasound machine 10 transmits ultrasound signals to a desired portion of the body, or more particularly, a desired portion of the heart, and receives the reflected ultrasound signals. The transmitted ultrasound signals are varied in intensity, with a high intensity burst destroying the microbubbles of the contrasting agent and lower intensity bursts not destroying the microbubbles. The reflected ultrasound signals are detected to determine the number of microbubbles present in the portion of the heart at a particular point in time, and then displayed, with the screen being brighter as the number of microbubbles increases.
The data relating to the number of microbubbles for various portions of the heart over time may be stored in a recording medium, such as a floppy disk or a compact disk or another medium. The recording medium would then be placed in a computer 20 and an analysis would be performed in the computer 20 to determine blood flow in a portion or in portions of the heart.
Alternatively, the ultrasound machine 10 could be connected to the Internet 30. Instead of storing the data in the recording medium as set forth immediately above, the data relating to the number of microbubbles for various portions of the heart over time would be transmitted over the Internet 30 and stored in an external location such as a website. The data would then be processed at the website, and the analysis would be performed to determine the blood flow in a portion or in portions of the heart.
The conventional technique is an extremely time consuming process and does not provide the doctor or technician with all the feedback she wants. A significant amount of processing is done off line to produce an image with a color overlay of white, grey, black, etc. In addition, this process takes a significant amount of time, so that if the ultrasound is not being performed properly during the time of receiving the ultrasound information, it would not be known until later that the procedure was improper and the subject would either have to have the ultrasound device applied to her again after waiting for the off line results or the subject would have to come back at a later date to reconduct the ultrasound test.
The present invention relates to a device for producing an image of a body part into which a contrasting agent has been introduced, the device comprising an image detecting device modifying the contrasting agent to provide a modified image, and a processor acquiring and processing the modified image so as to create an image which represents a rate of flow of blood or other fluid in the body part. The device may be an ultrasound imaging device or may be a magnetic resonance imaging device.
The processor processes the modified image on line or in real time, to more quickly enable a viewing of the blood or other fluid flow in the body part of concern, and quickly determine whether the test is being properly conducted.